The present invention relates to a bending machine for pipes, sections or similar.
The machine according to the present invention is a penetration-type pipe bending machine. Penetration-type bending machines comprise a fixed guide device having a longitudinal axis, for guiding the pipes in a feed direction; and a bending member movable with respect to the guide in a plane perpendicular to the longitudinal axis, and in turn comprising an annular guide, which, as the pipe is fed forward, deflects the pipe by displacement of the bending member in said plane.
The annular guide of known machines is made of sintered material, and has a circular pipe passage section substantially equal to the section of the straight pipe, so as to guide the pipe accurately and obtain precise bends.
Though extremely accurate, penetration machines of the above type have several drawbacks, on account of the annular guide requiring continuous lubrication to reduce friction between the pipe walls and the guide itself. Such machines therefore require a lubricating system, as well as degreasing of the bent pipes. Moreover, on account of the friction between the pipe and annular guidexe2x80x94still considerable despite lubricationxe2x80x94considerable force is required to push the pipe in the feed direction, thus possibly resulting in damage to straight pipes with thin or easily deformable walls.
Moreover, known sintered annular guides cannot be formed with polygonal passage sections, on account of the highly fragile nature of the corners, so that known bending machines of the above type cannot be used for bending polygonal-section pipes.
It is an object of the present invention to provide a pipe bending machine of the above type, designed to eliminate the drawbacks of the known state of the art.
According to the present inventions there is provided a pipe bending machine as claimed in claim 1.